1. Field of the Invention
The present invention relates to a golf club, and particularly to what is called a long-length golf club.
2. Description of the Background Art
A golf club is demanded to achieve an improved carry. In order to improve a carry, it is effective to increase a head speed of the golf club. In order to increase a head speed of the golf club, it is effective to increase a club length of the golf club. Therefore, a club length of the golf club tends to be longer. A club length of the golf club of 43 inches has previously been the mainstream, whereas a length of 45 inches is currently the mainstream. Currently, what is called a long-length golf club having a club length not shorter than 45.5 inches has also been used.
Simply increasing a club length of a golf club leads to greater moment of inertia, which results in difficulty in swinging the golf club. Then, it has been proposed to lessen moment of inertia of the golf club. For example, Japanese Patent Laying-Open No. 2000-185119 proposes a golf club that can lightly be swung. In the golf club in this publication, a weight which is a concentrated mass is additionally provided in the inside of the grip. This weight is provided within a range of 4 cm around a center of rotation of the grip. In addition, this weight is described as optimally weighing 5 g to 18 g. Moment of inertia of this golf club is thus lessened.
It has been found that, in a case where a club length of the golf club is increased in order to increase a head speed of the golf club, many golfers have not successfully achieved an increased head speed when the club length is increased to 45.5 inches or longer. One of factors may be that a club length of the golf club not shorter than 45.5 inches leads to difficulty in swinging the golf club due to increase in weight of the golf club or the like and a swing velocity (angular velocity) of the golf club lowers. It has thus been found that simply increasing a club length of a golf club does not lead to an increased head speed.
It is noted that attention is not paid to increase in head speed in the golf club in the publication above. In addition, the publication above does not note a long-length golf club either.